1. Field of the Invention
This invention relates to an apparatus using a disc-shaped record bearing medium, such as disc player.
2. Description of the Prior Art
In recording and/or reproducing apparatus using a rotation type record bearing medium of disc shape, for example, a rotation type flexible magnetic disc, rotation of the magnetic disc is performed after an engaging hole of the center core in the central portion of the magnetic disc has been engaged with a spindle which is driven to rotate by an electric motor. This type of apparatus displays a problem in that when the engagement of the center core with the spindle is loose, it becomes impossible to ensure that the magnetic disc undergoes normal rotative motion during recording or reproduction, and conversely when the aforesaid engagement is tightened, the magnetic disc becomes difficult to load on the spindle.
Therefore, as will be more fully described later with reference to FIG. 2, a method has been proposed wherein a magnetizable member is applied to the center core, while a magnet piece is mounted on the flanged portion of the spindle. However, even with such a magnetic coupling method, it is difficult to assure that when the center core is put on the spindle, it occupies a certain position relative to a reference surface, for example, the flange surface of the spindle. Therefore, it is difficult to hold the magnetic disc in a predetermined setting surface for maintenance of a predetermined aligning state between it and a recording and/or reproducing head. Also in a still picture recording and/or reproducing apparatus having a rigorous requirement for accuracy of alignment, the force necessary to load the center core on the spindle may amount to hundreds of grams. As the magnet piece is of large size, therefore, the size and weight of the apparatus is hindered from being reduced.
On the other hand, there has been proposed an apparatus provided with a mechanism for pressing a portion of the magnetic disc against the spindle as in a floppy disc device. Since, in this type of apparatus, that portion of the apparatus which drives rotation of the disc operates under the condition that the aforesaid mechanism applies a pressure on the spindle through the disc, its load becomes large, causing the speed of rotation to vary randomly.